Limu is the Hawaiian word for seaweed and is gathered by hand. While there are numerous types of limu there are about fourteen that can be considered common and edible. Typically limu was harvested from the reef at low tide or picked up along the shore where deposits would occur during high tide or heavy storms.

Ancient Hawaiians consumed more species of limu than any other Pacific Islanders. The task of both gathering and preparation was traditionally done by women. The kapu (taboo) associated with the consumption of limu was applied equally to both men and women. For example families for whom the shark was their aumakua (family or personal gods) refrained from eating the limu pakaiea because they beleived that young sharks were encased in this green algae.

Harvested limu was washed in freshed water, drained, chopped , pounded in a stone mortar and

then salted for flavor. Some types of limu prepared like this had to be consumed in a few days and was frequently combined with raw fish. Other types of limu were fermented and heavier amounts of salt was used as a preservative. Whatever form of preparation limu was used virtually to complement every foods. It was also an important source of minerals for the diet.

Today limu is more cultivated rather than hand-gathered along the shallow reefs and shorelines and remains a popular condiment with both Hawaiian and more contemporary dishes. However, there are also problems with invasive seaweed species that threaten the health of Hawaii's coral reefs. Volunteer efforts are needed from community members to help remove seaweed that has become too agressive.